H20 Designs Flowbox Waterbox


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Jun 22, 2006
I have burned through a tank now so I figured I could add my review. I purchased a used Flowbox, one of the early ones I am assuming (due to it not being powdercoated) and installed it in my Xjet with rear side exhaust (exits just at the right rear corner of the hull).

  • Great design, nice welds, looks good
  • The shape/size works well in my hull (SJ based) and it is very light, the thin profile gives great clearance for cables coming through the pole bracket
  • I like the mandrel bent tubing rather than 90 degree welded pieces, it might not equal more performance but it looks like it would
  • Sounds good, a bit louder than stock but not as loud as my previous TDR and Xmetal boxes

  • Had to play around with the angle it sat at to get the inlet to play nice with my FP dry pipe, this was tricky as it really wanted to push my pipe out of alignment
  • The mandrel bent in/out makes it pretty wide, I can't imagine it would fit in anything narrower than a RN (FX1) but most aftermarket hulls are likely wider
  • The outlet tubing seemed oversized, I am using a Rad Dude exhaust hose and didn't measure either so I cannot confirm if the outlet is too large or the RD tube is to small but it was a struggle to install on that end and didn't allow me to use the supplied T-Bolt clamp that came with the Rad Dudes tube
  • It would be too loud with front exhaust, or if you have sensitive water cops/waterfront property owners. It is borderline too loud with my rear side exhaust when it is out of the water but I will be moving my exhaust outlet to the rear this winter
Overall, its a nice piece, light weight, great design, sounds fast.


air blair

you are the reason
Feb 19, 2010
thumb, mich again
I have had a few of these Waterboxes and able to compare the performance is par with atp ,tdr,xmetal. They work great. The noise is appealing to me. The sizing is probably the only drawback. Kinda big for some of the big rocker skis people produce these days.

Air blair cell


New York Crew
Jan 17, 2006
Western New York
I've been rockin one for a few years now in my Foot Rocket... it's tall, so it can be tight in a hull with lots of rocker, but it's narrow, so it helps with shorter hulls with rocker. All-in-all, it fits perfect in a Foot Rocket. I have not had any issues at all with fit or function.
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